The Lateral Occipital Cortex Is Selective for Object Shape, Not Texture/Color, at Six Months

Abstract

Understanding how the human visual system develops is crucial to understanding the nature and organization of our complex and varied visual representations. However, previous investigations of the development of the visual system using fMRI are primarily confined to a subset of the visual system (high-level vision: faces, scenes) and relatively late in visual development (starting at 4 -5 years of age). The current study extends our understanding of human visual development by presenting the first systematic investigation of a mid-level visual region [the lateral occipital cortex (LOC)] in a population much younger than has been investigated in the past: 6 month olds. We use functional near-infrared spectroscopy (fNIRS), an emerging optical method for recording cortical hemodynamics, to perform neuroimaging with this very young population. Whereas previous fNIRS studies have suffered from imprecise neuroanatomical localization, we rely on the most rigorous MR coregistration of fNIRS data to date to image the infant LOC. We find surprising evidence that at 6 months the LOC has functional specialization that is highly similar to adults. Following Cant and Goodale (2007), we investigate whether the LOC tracks shape information and not other cues to object identity (e.g., texture/material). This finding extends evidence of LOC specialization from early childhood into infancy and earlier than developmental trajectories of high-level visual regions.

Perceptual Function and Category-Selective Neural Organization in Children with Resections of Visual Cortex

“…The human ventral occipitotemporal cortex (VOTC) has a well established medial-to-lateral arrangement of category-selectivity bilaterally (Grill-Spector and Malach, 2004) and a clearly-defined pattern as a function of eccentricity (Hasson et al, 2002). This selectivity and topography appear to emerge early in life, revealed by both fMRI (Scherf et al, 2007;Golarai et al, 2017;Barttfeld et al, 2018;Dehaene-Lambertz et al, 2018) and functional nearinfrared spectroscopy studies (Otsuka et al, 2007;Emberson et al, 2017), and then be refined further over development (Nishimura et al, 2015;Deen et al, 2017). The correspondence between this cortical arrangement and perceptual behavior, and the extent to which this relationship is malleable, remains controversial.…”

The shape of novel objects contributes to shared impressions

“…Infants as young as 4.5 months have been found to individuate objects using their shape, months before the ability to individuate objects based on their patterns or colors is demonstrated (Wilcox, 1999). And it has been shown that infants as young as 6 months are already equipped with a region of their brain selectively activated to changes in shape (Emberson, Crosswhite, Richards, & Aslin, 2017).…”

Functional outcomes following lesions in visual cortex: Implications for plasticity of high-level vision

“…Research over the past two decades has indicated that cortical areal formation follows a unique, spatiotemporal time-lapse sequence during childhood and through early adulthood (Gogtay et al, 2004) with different maturational trajectories for different areas and some regions not fully mature until well into adolescence. For example, face-selective cortex follows a slower developmental trajectory, not fully mature even in early adulthood (Germine et al, 2011), compared to object-selective cortex, which may be adult-like as early as age 5 (Gogtay et al, 2004; Golarai et al, 2015, 2010, 2007; Haist et al, 2013; Scherf et al, 2011, 2007) or even younger (Emberson et al, 2017; Nishimura et al, 2015). The pattern of word selectivity in the VWFA also emerges slowly over development, as reading and writing experience accumulate (Maurer et al, 2006), and orthographic representations may develop at the expense of face representations in the LH (Cantlon et al, 2011; Dehaene et al, 2015; Dundas et al, 2013).…”